Which of the following statements are false regarding the muscle structure? I. In the centre of each I-band is an elastic fibre (Z-line) which bisects it II. Thin filament are firmly attached to the Z-line III. M-line is a fibrous membrane in the middle of A-band IV. A sarcomere comprises one full-A band and two half I-bands
a)	I and II
b)	III and IV
c)	II and III
d)	None of these

(d)

None of these.

The thick filaments lies parallel to one another and thin filaments are present in orderly array between the thick filaments. In the centre of the I-band, there is a band of amorphous material called Z-line. In the middle of the A-band a comparatively less dark zone called H-zone of band is present. The area between the two Z-lines is called sarcomere. M-line is present, in the middle of H-zone.

In the centre of each I-band is an elastic fibre called Z-line which bisects it. The thin filaments are firmly attached to the Z-line. The thick filaments in the A-band are also held together in the middle of this band by thin fibrous membrane called M-line. The A and I-band are arranged alternately throughout the length of myofibrils. The portion of the myofibrils between two successive Z-lines is considered as the functional unit of contraction called sarcomere